Recirculating-type gas-blast doublebreak circuit interrupter with filtering housing surrounding intermediate contact



March 1967 w M. LEEDS 3309,42

RECIRCULATING-TYPE GAS-BLAST DOUBLE-BREAK CIRCUIT INTERRUPTER WITHFILTERING HOUSING SURROUNDING INTERMEDIATE CONTACT Filed Nov. 22, 1965 I5 $heets $heet 1 INVENTOR Winthrop M. Leeds BY MM W ATTORNEY 3 309 482UIT W. M. LEEDS March 14, 1967 -BREAK CIRC INTERRUPTER WITH FILTERINGHOUSING SURROUNDING RECIRCULATING-TYPE GAS-BLAST DOUBLE INTERMEDIATECONTACT 5 Sheets-Sheet 2 Filed Nov. 22, 1965 3,309,482 UIT March 14,1967 w. M. LEEDS RECIRCULATING-TYPE GAS-BLAST DOUBLE-BREAK CIRCINTERRUPTER WITH FILTERING HOUSING SURROUNDING INTERMEDIATE CONTACT 3$1198 tS-Sheet 3 Filed Nov. 22, 1965 g HA M g 3 mm E mm NM 6 o J N m mmFm mm Jmm\ mm mm W U mv mm 7 1 7 f M 4; mm K United States Patent Office3,309,482 Patented Mar. 14, 1967 RECIRCULATING-TiKPE GAS-BLAST DOUBLE-BREAK CIRCUIT INTERRUPTER WITH FIL- TERING HOUSING SURRUUNDING INTER-MEDIATE CQNTACT Winthrop M. Leeds, Forest Hills Bore, Pittsburgh, 1 21.,

assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., acorporation of Pennsylvania Filed Nov. 22, 19 65, Ser. No. 509,064Claims. (Cl. 200-148) This application is a continuation-in-part of US,application filed Apr. 17, 1961, Ser. No. 103,651, now aban doned.

This invention relates to circuit interrupters in general, and, moreparticularly, to circuit interrupters of the gasblast type.

A general object of the present invention is to provide an improved,highly-effective, gas-blast circuit interrupter in which impedancemeans, such as resistance means, are employed to assist in theinterruption of the main current are, thereby lowering the rate .of riseof the recovery voltage transient, and at the same time in which meansare provided to assist in the purification of the utilizedarcextinguishing gas.

In the United States Patent 3,214,553 issued to Winthrop M. Leeds, andassigned to the assignee of the instant application, there is disclosedand claimed various gas-blast types of circuit interrupters in which thearc-extinguishing gas is directed into filtering elements prior to itssubsequent exhausting into the main interior of the tank structure forreuse. It is a further object of the present invention to improve uponthe types of interrupting structures set forth in the aforesaid patent,rendering them more compact and more efficient in operation.

In US. Patent 3,160,726, issued Dec. 8, 1964, to Charles F. Cromer, andalso assigned to the assignee of the instantapplication, there isdisclosed and claimed a gas-blast interrupting unit, particularlyadaptable for a high-power circuit interrupter, in which a tubularintermediate contact is co-operable with a relatively stationary maincontact having a resistance shunt therebetween. A series isolatingcontact is employed to interrupt the residual current arc followingextinction of the main break arc. It is an additional object of thepresent invention to extend the principles set forth in thelast-mentioned patent, rendering them more applicable to a high-powercircuit interrupter in conjunction with suitable filtering elements.

Further objects and advantages will readily become apparent upon readingthe following specification, taken in conjunction with the drawings, inwhich:

FIGURE 1 is an end elevational view of a three-pole high-power circuitinterrupter embodying features of the present invention;

FIG. 2 is a substantially vertical sectional view taken through one ofthe tank structures of FIG. 1, illustrating the bridgingarc-extinguishing assemblages, the contact structure being illustratedin the closed-circuit position;'

FIG. 3 is a considerably-enlarged view, in section, taken substantiallythrough the righthand arc-extinguishing unit of FIG. 2, and illustratingthe contact structure in the closed-circuit position;

FIG. 4 is a substantially vertical sectional view taken through the sameinterrupting unit, as is illustrated in FIG. 3, but the contactstructure is illustrated in the fully open-circuit position; and,

FIG. 5 is a diagrammatic view of the circuit interrupter of FIGS. 1-4illustrating the general path of the electrical circuit passing throughthe interrupter.

Referring to the drawings, and more particularly to FIG. 1 thereof, thereference numeral generally designates a dual-pressure gas-blast type ofcircuit interrupter.

As shown, the circuit interrupter 10 is of the high-power type involvinga group of three generally horizontally-extending grounded tankstructures 11 spaced apart, and simultaneously mechanically actuated byan operating mechanism, not shown, disposed within a mechanism housing12 situated adjacent one of the three tank structures 11.

As shown in FIG. 1, a pair of terminal bushings 13, 14 extend downwardlywithin each of the three tank structures 11 for carrying the circuit toan arc-extinguishing assemblage 15 (FIG. 2), which mechanically andelectrically bridges the lower ends 16, 17 of the terminal bushings 13,14, respectively.

Located adjacent the lower end of each of the three tank structures 11is a drive-shaft 18, which passes through a .sealed gas-tight opening,not shown, externally of the tank structure 11, and is externallyactuated by a suitable drive-crank 19. The three drive-cranks 19 aremechanically connected together for simultaneous operation by amechanism, not shown, disposed within the mechanism housing 12 (FIG. 1).

With reference to FIG. 2, it will be observed that there are providedthree gas-blast interrupting units, generally designated by thereference numeral 21), disposed in series for interrupting the currentpassing through the circuitinterrupting structure 15. The bridgingarc-extinguishing assemblage 15 not only comp-rises the three gas-blastinterrupting units 2%), but also it comprises a high-pressure reservoirchamber 21, disposed at the right-hand end of the extinguishingassemblage 15, as viewed in FIG. 2. To control the passage ofhigh-pressure gas out of the highpressure reservoir chamber 21, there isprovided a gasblast mechanism, generally designated by the referencenumeral 22, and more particularly set forth in detail, and its functiondescribed, in United States Patent 3,164,704 issued I an. 5, 1965 toRussell N. Yeckley, Joseph Sucha and Roswell C. Van Sickle, and assignedto the assignee of the instant application. I

For the purpose of understanding the present invention, however, it ismerely necessary to know that the operation of the gas-blast mechanism22 effects opening of a blast valve 23 (FIG. 3), and permits a blast ofhigh-pressure gas to pass from the reservoir chamber 21 through an inletpassage 24 and into the first, or right-hand interrupting unit 20 of theassemblage 15. The gas blast also blasts through a pair of blast-tubes25, 26 and into the adjaoently-disposed gas-blast interrupting units 20'to effect extinction of the arcs therein.

An insulating feed conduit 27 feeds high-pressure gas from anexternally-provided compressor disposed within the mechanism compartmentpressure storage tank 21 in each of the three tank structures 11 toreplenish the high-pressure gas which is used up 1czuring the openingoperations of the circuit interrupter Mechanically interconnecting aninternal crank-arm 28, afiixed to the drive-shaft 18, with the gas-blastvalve operating mechanism 22 is an insulating operating rod 29. Inaddition, the operating rod 29 mechanically operates a movable contactassemblage, generally designated by the reference numeral 30, andcomprising a pair of longitudinally-extending operating rods 31 bridgedby transverse cross-bars 3-2 carrying movable disconnecting contacts 33adjacent the middle portions thereof.

As illustrated in FIGS. 3 and 4, the movable disconnecting contact 33 ofeach gas-blast interrupting unit 20 engages a tubular intermediatecontact 34, which moves with the disconnecting contact 33 toward the endof the closing operation. As illustrated in FIG. 3, the disconnectingcontact 33 forces the movable tubular intermediate contact 34 intocontacting engagement with a relatively stationary contact, generallydesignated by the ref- 12 (FIG. 1 to the high- I (3 erence numeral 35. Abiasing spring 36, which may comprise a battery of individual springs33a, biases the tubular movable intermediate contact 34 toward theopen-circuit position, as shown in FIG. 4.

As illustrated in both FIGS. 3 and 4, the relatively stationary contactstructure 35, comprises a plurality of ann-ularly-dis-posed segmentalflexible contact fingers 37 and a substantially centrally-disposedarcing horn 38. During the opening operation, a main current are 39,illustrated in FIG. 4, is drawn between the relatively stationarycontact structure 35 and the movable tubular intermediate contact 34.This main are 39 is shunted by an impedance means 40, in this particularinstance comprising a resistance 41. Preferably, the resistance 41 is inthe form of a helically-shaped coil of high-resistance coiled wire. Theresistance 41 is supported by a plurality of annularly-disposedinsulating support rods 42, which are supported by a bracket 43 from theend casting 44 at one end, and at the other end by an electrostaticmetallic shield 44a. A flexible shunt 45 electrically interconnects theleft-hand end of the resistance coil 41 with a resistor terminal 46,which constitutes an integral part of a relatively stationary metallicfilter housing 47, containing a suitable filtering material 48.Preferably the filtering material 48 comprises suitable mesh screeningand preferably, in the case of sulfur-hexafiuoride (SP gas, activatedalumina.

Preferably the metallic filter housing 47 constitutes a guiding meansfor movement of the intermediate tubularshaped contact 34 and alsoprovides a spring seat for the intermediate contact compression spring36. It is supported from a pair of spaced-apart stationary insulatingtie-bars 67 by means of insulating cross-bars as of generally T-shape.Bolts 68a fixedly secure the several crossbraces 68 to the left handends of the filter housings 4-7, as shown more clearly in FIG. 4.

To assist in directing the released gas blast from the high-pressurechamber 21 by opening of the blast valve 23, an insulating flow director49 is provided. As illustrated more particularly in FIG. 4, the flowdirector 49 directs the gas blast within the interior 50 of the movabletubular intermediate contact 34. The intermediate contact 34 is providedwith side venting ports 51, which direct all the arced gas into thefilter housing 47, and thereby compel all the same to be purified priorto ultimate exhaust into the general interior 52 within the main body ofthe tank structure 11.

As well known by those skilled in the art, the provision of the shuntingimpedance 40 assists in the interruption of the main current are 39 andimproves the power factor of the circuit, while at the same timelowering the rate of rise of the circuit to be interrupted. The residualcurrent arc 53 is interrupted at the series isolating gap comprising thedisconnecting contact 33 and the arc-horn portion 54 of the intermediatecontact 34.

Although FIG. 4 illustrates the fully open-circuit position of theseveral contact parts, nevertheless, for purposes of illustration, themain current are 39 and the residual current are 53 have been drawn intothe figure for the purpose of clarifying the description of the openingoperation of the interrupter.

It will be observed that the movable disconnecting contact 33 comprisesan annularly-disposed finger cluster 55, and an interiorly-disposedfinger cluster 56. In the closedcircuit position, as shown in FIG. 3,the annularlydisposed fingers 55, 56 make contacting engagement withsimilar fingers 57 constituting an end portion of the intermediatecontact 34.

FIG. diagrammatically illustrates the electrical circuit passing throughthe tank structure 11. The movable contacts 34, 35 which open first aredesignated by the reference numeral 1. The series disconnecting contacts33, 34, which open subsequently to the opening of the main contacts 1are, in FIG. 5, designated by the reference numeral 2. With reference toFIG. 5, it will be apparent that opening of all of the main breaks 1will cause the circuit to pass through the shunting resistance sectionsR, and following opening of the disconnecting contacts 2 will interruptthe residual current passing through the resistance sections 41, whichis of lower amperage and of a higher power factor than the main currentarcs .39.

In the closed-circuit position of the interrupter 19, illustratecl inFIGS. 2 and 3, it will be apparent that the circuit through theinterrupter comprises terminal bushings 13, 14, end clamps 16, 17, andthe several interrupting units 2a, each of which passes the currentthrough the disconnecting contacts 33, intermediate contact 34, to thestationary contact 35 thereof.

A battery of accelerating compression springs 58 (FIG. 2) is provided toeffect leftward opening biasing action upon the movable contactassemblage 30. When the mechanism within mechanism housing 12 (FIG. 1)is released or unlatched, the several insulating operating rods 29 havetheir tensile stress released, and the accelerating spring 58 in each ofthe tank structures 11 take over, and very quickly effect leftwardopening movement of the several movable contact assemblages 31). Withreference to FIG. 4, it will be noted that the leftward opening movementof each of the movable disconnecting contacts 33 will permit the batteryof compression springs 36, associated with each gas-blast interruptingunit 21), to force the movable tubular intermediate contact 34 intofollowing engagement with the disconnecting contact 33, therebyeffecting a separation between the tip end 59 of intermediate contact 34and the contact fingers 37. This will draw a main current arc 39 shownin F116. 4. Simultaneously with the leftward opening movement of themovable contact assemblies 30, the blast-valve mechanism 22 is actuatedto cause thereby clockwise rotation of a pivotallymounted blast-valvelever 59, as set forth in aforesaid Patent 3,164,704, to open the blastvalve 23, and to let the resulting gas blast carry the main current arc39 inwardly to terminate upon the arcing horn 38. The gas blast movesthe left-hand terminal of the are 39, as viewed in FIG. 4, along theinner surface 60 of the movable tubular intermediate contact 34 in amanner more fully explained in the United States Patent 3,154,658 issuedOct. 27, 1964, to Robert G. Colclaser, In, and Russell N. Yeckley, andassigned to the assignee of the instant application.

Because of the provision of the shunting impedance 40, and also becauseof the intensive gas blast, directed by the flow director 49 interiorlywithin the region 50 of the intermediate contact 34, the main-currentarc 39 is quickly extinguished, all of the gas blast, following arc,passing through the lateral port openings 51 and into the filter housing47.

When the flange portion 61 of the intermediate contact 34 strikes thestop as constituting the left-hand wall of the filter housing 47, asviewed in FIG. 4, the intermediate contact 34 will be halted in itsleftward opening movement, thereby permitting the movable disconnectingcontact 33 to pull away from it, and to draw a relatively small-amperageresidual-current arc 53. This are 53 has a low amperage, and at thistime the circuit has a relatively high power factor. Consequently, theare 53 is easily interrupted. Continued opening movement of the movabledisconnecting contact 33 results in interposing a series isolating gapinto the circuit to thereby enable the circuit interrupter 10 towithstand surge voltages, such as lightning surges in the fullyopen-circuit position of the interrupter 10.

It will be observed that the provision of the filter housing 47 compelsall of the sulfur-hexafiuoride (SP gas to pass through the filteringmaterials 43 prior to subsequent exhaust into the general interior 52 ofthe tank 11.

It is particularly important to catch metallic fluoride powders withscreens or filters, since these powders, although good insulation whendry, are hydroscopic and take up moisture very easily when, forinstance, a breaker is opened for inspection of the contacts. However,the activated alumina which is provided to purify the gas of activegaseous are products could alternatively be placed in other locations inthe tank where its purifying function could take place over a somewhatlower period of time, as indicated by the filter container 470.

It is well known that resistors of the proper magnitude placed inparallel with the arcing contacts of a power circuit breaker aid theinterruption of short-circuit currents by controlling the rate of riseof recovery voltage. The present invention is, in part, concerned withnovel sulfur-hexatluoride breaker arrangements for using resistors, incombination with flow channels for the gas, which are directed throughscreens and filters. Although the present invention has been describedin connection with the particular use of sulfur-hexafluoride (SP gas asthe arc-extinguishing gas, it is to be clearly understood that theinvention is not limited solely to this particular gas alone, but may beemployed with any other gas, which needs purification prior tosubsequent reuse.

The power circuit breaker 10, shown in FIGS. 1-4 of the drawings,illustrates a 230 kv., SF dead tank breaker constructed to incorporatethe use of a shunting resistance 41 and the additional use of afiltering element 47. It is to be emphasized that the provision of aspecial exhaust chamber 47 with screens and a filter 48 is verydesirable to clean up the arced SP gas before it is released into themain low-pressure tank 11, where the insulating parts are located.Particular advantages of the construction illustrated in FIG. 2 are thatfewer main breaks are required, and filtering of the are products isobtained to keep the breaker clean.

To effect the closing of the circuit interrupter 10, the mechanism, notshown, disposed within the mechanism housing 12 is effective to cause,through suitable linkage, not shown, counterclockwise rotative closingmotion of the several external crank-arms 19, shown in FIG. 2. Thecounterclockwise rotation of the several crank-arms 19 effectscorresponding counterclockwise rotation of the several drive shafts 18and consequently generally leftward closing movement of the insulatingoperating rods 29. Since the right-hand ends of the insulating operatingrods 29 are connected, as at 66 (FIG. 3) to a crank-arm 67 pivotallymounted on a fixed pivot axis 68, a floating link 69, pivotallyconnected, as at 70, to the crank-arm 67 is effective to effectrightward closing movement of the two insulating operating rods 31 ofthe movable contact assemblage 30. This closing movement of the severalmovable contacts 33 will charge the accelerating spring 58 and alsoeffect contact closure, first at the contact breaks 33, 57 andsubsequently at the main breaks 59, 37. Reference may be had to UnitedStates Patent 3,057,983, issued Oct. 9, 1962, to Russell N. Yeckley,Joseph Sucha and Benjamin P. Baker and assigned to the assignee of theinstant application for further details of operation of the interrupter10.

From the foregoing description of an interrupting structure embodyingfeatures of the present invention, it will be apparent that there isprovided a novel circuit-interrupting structure, in which impedancemeans are employed to shunt the main breaks; and subsequently, theresidual current through the impedance means is interrupted atresistance breaks.

Although there has been illustrated and described a specific structure,it is to be clearly understood that the same Was merely for the purposeof illustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing from the spiritand scope of the invention.

I claim as my invention:

1. A gas-blast circuit interrupter of the recirculatinggas typeincluding a relatively stationary contact, a movable tubularintermediate contact through which gas may flow and a movabledisconnecting contact cooperable with said movable intermediate contactto establish an isolating break, means for directing a flow ofcompressed gas into the movable tubular intermediate contact during theopening operation to extinguish the are established between therelatively stationary and intermediate contacts, a filter housingsubstantially surrounding the tubular intermediate contact, and ventingmeans (51) provided in the side Wall of the movable tubular intermediatecontact for directing all of the gas flow into the surrounding filterhousing prior to exhaust for subsequent reuse.

2. The recirculating gas-blast circuit interrupter of claim 1, wherein abiasing spring for the movable tubular intermediate contact is seatedwithin said filter housing.

3. The recirculating gas-blast circuit interrupter of claim 1, whereinthe filter housing guides the opening and closing movement of themovable tubular intermediate contact. v

4. The recirculating gas-blast circuit interrupter of claim 1, whereinan insulating flow director (49) directs all of the gas flow into theinterior of the movable tubular intermediate contact to carry oneterminal of the established main current are thereinto.

5. The combination according to claim 3, wherein impedance means shuntsthe stationary and intermediate contacts, and the filter housing servesas a terminal for one end of the impedance means.

References Cited by the Examiner UNITED STATES PATENTS 2,125,525 8/1938Thommen 200-148 3,160,726 12/1964 Cromer 200- X 3,164,705 1/1965 Cromer200148 3,221,129 11/1965 Young 200148 ROBERT K. SCHAEFER, PrimaryExaminer. ROBERT S. MACON, Examiner.

1. A GAS-BLAST CIRCUIT INTERRUPTER OF THE RECIRCULATINGGAS TYPEINCLUDING A RELATIVELY STATIONARY CONTACT, A MOVABLE TUBULARINTERMEDIATE CONTACT THROUGH WHICH GAS MAY FLOW AND A MOVABLEDISCONNECTING CONTACT COOPERABLE WITH SAID MOVABLE INTERMEDIATE CONTACTTO ESTABLISH AN ISOLATING BREAK, MEANS FOR DIRECTING A FLOW OFCOMPRESSED GAS INTO THE MOVABLE TUBULAR INTERMEDIATE CONTACT DURING THEOPENING OPERATION TO EXTINGUISH THE ARC ESTABLISHED BE-